Fatigue of metals is a subject of practical importance because many components and structures in service are subjected to varying loads and although the average stresses are often low, local concentration of stresses do not reduce the static strength but often lead to failure by fatigue. Micro-crack formation due to fatigue is more in ferritic-pearlitic annealed steel rather than in hardened an...

Cement-based concrete is the most widely used building and construction material in the world. Although concrete itself is relatively durable when used under the mild environments, its intrinsic weak tensile strength greatly limits its application due to its porous structure. Traditional strategies to overcome this weakness of concrete include utilization of various reinforcing materials, such ...

Quasi-static and dynamic damage mechanisms in alumina tiles were investigated. The tiles were under a variety of boundary conditions at the tile's edges during impact NATO 0.3 cal. AP rounds with hardened and sharpened steel core were used. The alumina tile samples were 50x50 mm2 area, the thicknesses ranging from 5 to 12 mm. 'he tiles were mounted in a special confinement frame, which enabled ...

Quasi-static and dynamic damage mechanisms in alumina tiles were investigated. The tiles were under a variety of boundary conditions at the tile's edges during impact NATO 0.3 cal. AP rounds with hardened and sharpened steel core were used. The alumina tile samples were 50x50 mm2 area, the thicknesses ranging from 5 to 12 mm. 'he tiles were mounted in a special confinement frame, which enabled ...

Within the framework of a systems approach, the design of a high performance stainless steel integrated processing/structure/property/performance relations with mechanistic computational models. Using multicomponent thermodynamic and diffusion software platforms, the models were integrated to design a carburizable, secondary-hardening, martensitic stainless steel for advanced gear and bearing a...

The wear mechanisms of cutting tools made of tungsten-carbide (WC), PCBN and PCD were investigated using the tool life and temperature results available in the literature. For tool/work combinations WC/steel and PCBN/hardened-steel, under practical conditions, tool wear was found to be greatly influenced by the temperature. It was concluded that the most likely dominant tool wear mechanism for ...

Precipitation-hardened (PH) stainless steels have been widely used as structural materials and related applications in marine environments, power plants (light-water and pressurized water reactors), and chemical industries because of their good mechanical properties and corrosion resistance at typical service temperatures below 300oC. 17-4 PH (A1S1630) stainless steel (15–17.5 Cr, 3–5 Ni, 3–5 C...

An experimental investigation with Nd:YAG laser system was carried out to study the effects of laser hardening process parameters on the microstructure and hardness during laser hardening of EN25 steel. The laser beam is allowed to scan on the surface of the work piece by varying the laser beam power (750–1250 W) and travel speed (500–1000 mm/min) of the work table. The microstructural features...

As the turbine industries need to manufacture turbine blades made of martensitic stainless steel AISI 420 with high toughness and wear resistance, local laser hardening has become more and more important. In this research, surface of the samples was initially hardened by high-power pulsed laser beam; then, optimum parameters of hardening were calculated and wear resistance of surface hardened s...

Elliptical vibration cutting technology is well-known for its excellent performance in ultraprecision machining of steel materials with single crystal diamond tools. This paper presents two approaches to attain high-performance microand macro-scale sculpturing for steel materials by utilizing elliptical vibration cutting. In order to attain free-form sculpturing in macro-scale, a 4-axis control...